Some UVs appearing dark/inverted when light baking

[marloui]

As the title says, I've encountered this issue where some UVs appear dark or inverted. It only looks "off" in Substance Painter (when using the "Baked Lighting Environment" filter); in Maya and UE4 everything looks fine. I checked in Maya to ensure the normals are facing the right direction, the UVs aren't flipped, there's no overlap. Tried Freeze transforms and Unlock normals but the problem persists.

This thread describes exactly the problem I'm having, but there doesn't seem to be a definitive solution. I tried the methods listed but they didn't solve the problem either.
https://forum.substance3d.com/index.php?topic=12806.0

It seems like the problem lies within Maya and using the Mirror tool, since mirroring meshes requires Scale -1. In that case, how can I change my workflow so that these kinds of bake issues don't occur in SP?

[GeoffroySC]

Hi,

I believe this is a known bug. If you mirrored this mesh, could you try applying all the transforms? 

Thank you,
Kind Regards,
Geoffroy SC

[marloui]

Thank you for the reply. I tried applying all transforms in Maya, and adjusting different settings (such as Freeze transforms > Lock normals > Always, checking and unchecking Preserve normals), but the same problem still occurs in SP.

[marloui]

I just realized I might've misunderstood what you meant, hence my last reply. But I now mirrored the entire mesh, applied transforms and imported into SP. The whole mesh is looks dark/inverted now except the "problem areas" from before, that look correct.